PEK-KWL-HKG is a relatively expensive route, no matter how you slice it. If it makes you feel any better, PEK-HKG itself is also on the pricey side (you're basically getting the KWL stopover for free).

Regarding drivers, I suggest you go to the relevant thread, and work backwards (i.e. call the most recent drivers first). Or, if you want to save money, and are traveling on a weekend, join the "hiking around Beijing" group on beijingstuff.com.